formal UK /ˈfɔːməl/US /ˈfɔɹməl/adjective 9noun 6forms 3 adjective9 •done in the correct, serious way that social rules expect, and not relaxedHe's always very formal, and I wish he'd relax a bit. •Ceremonial or traditional.Formal wear must be worn at my wedding! •Official.I'd like to make a formal complaint. •In accordance with established forms.She spoke formal English, without any dialect. •In accordance with a methodological framework with well-defined rules or laws; rigorous.Despite efforts by limnologists and freshwater biologists to create a formal definition of “pond”, there is still no universal distinction between a “pond” and a “lake”.Only formal proofs, which derive theorems logically from their given axioms, are considered satisfactory in modern mathematics. •Organized; well-structured and planned.When they became a formal club the rowers built a small boathouse. •Relating to the form or structure of something.Formal linguistics ignores the vocabulary of languages and focuses solely on their grammar. •Relating to mere manipulation and construction of strings of symbols, without regard to their meaning.Formal series are defined without any reference to convergence. •Relating to formation.The formal stage is a critical part of any child's development. noun6 •An event with a formal dress code.Jenny took Sam to her Year 12 formal. •An evening gown.Well, I open up the door / And much to my surprise / The girls were wearin' formals / And the boys were wearin' ties — 1965 •A formal parameter. •Formalin. •Ellipsis of formal hall. •An acetal formed from formaldehyde. formsformals · more formal · most formal